Yasuhiro Okabe

Effect of Milrinone on Ischemia-Reperfusion Injury in the Rat Kidney

BACKGROUND Milrinone (MIL), a phosphodiesterase (PDE) 3 inhibitor, exhibits cardiotonic and angioectatic effects. Various PDE inhibitors have been shown to suppress inflammatory cytokines. In this study, we evaluated the angioectatic and anti-inflammatory cytokine effects of MIL on renal function after warm ischemia in a rat ischemia-reperfusion (I-R) injury model. MATERIALS AND METHODS MIL or control solution was perfused from the left renal artery to the right kidney, and the left kidney was excised. The right renal artery, vein, and ureter were clamped and then released after 50 minutes to produce warm ischemia. We evaluated control (n = 7), MIL (n = 7), and sham operation (n = 7) groups for serum creatinine, blood urea nitrogen (BUN), blood flow, expression of tumor necrosis factor (TNF)-α mRNA, apoptosis index, and histological evidence of acute tubular necrosis. RESULTS Serum creatinine and BUN concentrations peaked at 24 hours after reperfusion. MIL treatment significantly reduced serum creatinine (control group 1.27 ± 0.45 mg/dL vs MIL group 0.77 ± 0.19 mg/dL, P < .05; sham 0.35 ± 0.2 mg/dL) and BUN (control 67.6 ± 13.6 mg/dL vs MIL 51.0 ± 8.8 mg/dL, P < .05; sham 23.0 ± 4.2 mg/dL) levels at 24 hours. Thereafter, serum creatinine and BUN concentrations in the MIL group remained significantly lower compared with the control group for 120 hours (P < .05). MIL group exhibited significantly higher tissue blood flow, less acute tubular necrosis, lower expression of TNF-α mRNA in renal tissue, and lower apoptotic index (P < .05). CONCLUSIONS MIL maintained renal tissue blood flow by its vasodilatory effect, suppressed expression of TNF-α mRNA by increasing intracellular cyclic adenosine monophosphate, and ultimately decreased tubular cell apoptosis, thus protecting renal function after warm I-R injury.

One-year follow-up of treatment with once-daily tacrolimus in de novo renal transplant

OBJECTIVES The once-daily prolonged-release formulation of tacrolimus (tacrolimus QD) is expected to demonstrate equivalent efficacy and safety to the twice-daily formulation (tacrolimus BID). We reviewed the 1-year outcomes of tacrolimus QD in de novo renal transplant. MATERIALS AND METHODS We reviewed 50 de novo renal transplant patients assigned in a nonrandomized fashion to either tacrolimus QD (n=23, historic control group) or tacrolimus BID (n=27). Other immunosuppressive drugs used in both groups included mycophenolate mofetil, basiliximab, and steroids. We evaluated trough levels, required dosages, renal function, rejection rates, and episodes of infection within 1 year after transplant. RESULTS Trough levels of both drugs varied during the perioperative periods, but subsequently stabilized in both groups. There was a tendency toward a slow elevation and a higher dosage requirement in the tacrolimus QD group, compared with the tacrolimus BID group in the early stages, though the required dosages decreased steadily. The rejection rate in the tacrolimus QD group was low, and only 1 patient experienced subclinical rejection. No severe infectious adverse events were observed. CONCLUSIONS Patients taking tacrolimus QD tended to have lower trough levels and require higher dosages than those taking tacrolimus BID during the early posttransplant period, though the differences decreased with increasing time after transplant. Tacrolimus QD can be administered with excellent efficacy and safety in de novo renal transplant recipients.

Availability of Pancreatic Allograft Biopsies Via a Laparotomy

OBJECTIVE The aim of this study was to evaluate the availability of a pancreatic allograft biopsy via a laparotpmy. PATIENTS AND METHODS From September 2004 to November 2007, 17 pancreas transplantations were performed: 15 simultaneous pancreas and kidney transplantations (SPK), 1 pancreas transplant alone (PTA), and one pancreas after kidney transplantation (PAK). Thirteen pancreatic allograft biopsies were obtained via an open laparotomy. This study evaluated the complications associated with this procedure, the rate of obtaining an adequate sample, and the relationship between biopsy-proven rejections and laboratory markers. In SPK cases we evaluated the synchronization between pancreas and kidney rejection. The pancreatic samples were diagnosed according to the Drachenberg classification. RESULTS No complications resulted from the procedure. The rate of obtaining adequate samples was 84.6%. Pancreas rejection correlated with elevation of the laboratory markers in 71.4%. Simultaneous pancreas and kidney rejection occurred in 62.5%, only kidney in 25%, and only pancreas in 12.5%. CONCLUSION A pancreas graft biopsy was absolutely imperative to improve the outcome in PTA, and even in SPK cases. A pancreatic allograft biopsy via a laparotomy was a safe, necessary and easy procedure to obtain an accurate diagnosis of rejection among pancreas transplantation patients.

Protocol biopsy findings in living donor kidney transplant patients treated with once-daily or twice-daily tacrolimus formulation

BACKGROUND Once-daily extended-release tacrolimus (Tac-QD) has been shown to have equivalent efficacy and safety to the twice-daily formulation (Tac-BID) in kidney transplant patients. However, detailed comparison of allograft pathology found on a protocol biopsy (PB) in Tac-QD- versus Tac-BID-based regimens has not been described. METHODS We retrospectively investigated 119 de novo living donor kidney transplant patients treated with Tac-QD (n = 90) or Tac-BID (n = 29) and their 3- and 12-month PB results. Other immunosuppressive drugs administered included basiliximab, mycophenolate mofetil, and methylprednisolone. We evaluated daily doses and trough levels of Tac and serum creatinine levels, and compared pathologic findings. RESULTS Daily doses were higher in the Tac-QD group, but trough levels and serum creatinine levels were comparable. On 3- and 12-month PB, the frequency of subclinical rejection was similar between the groups, whereas interstitial fibrosis and tubular atrophy (IF/TA) were less common in the Tac-QD group at 12 months (42.2% vs 20.6%, P = .04). Univariate and multivariate logistic regression analyses revealed that allograft rejection (borderline changes or higher) was associated with IF/TA (odds ratio 4.09, 95% confidence interval 1.76-10.10, P = .001). The Tac-QD-based regimen showed a trend toward the absence of IF/TA but it did not reach statistical significance. Tubular vacuolization and arteriolar hyaline changes were also comparable in the two groups. CONCLUSIONS We found a trend toward milder IF/TA, but no significant differences in kidney allograft pathology in patients who were administered Tac-QD- versus Tac-BID-based regimens at 12 months. The effects of Tac-QD on chronic allograft injury must be studied by longer observation.

Early Disappearance of Urinary Decoy Cells in Successfully Treated Polyomavirus BK Nephropathy

BACKGROUND Polyomavirus BK nephropathy (BKVN) is an important infectious complication in kidney transplant patients. Regular screening using polymerase chain reaction for BK virus DNA in plasma and urinary cytology is effective for early diagnosis of BKVN. However, methods of follow-up and therapeutic targets are not well described. METHODS Ten patients with BKVN who received biweekly urinary cytology and repeat biopsies after diagnosis were retrospectively studied. Histological remission of BKVN was determined when biopsy revealed negative SV40 large T-antigen (TAg) staining. Results of urinary cytology and repeat biopsy findings were compared. RESULTS Urinary decoy cells disappeared in 8 of 10 patients 55 ± 25 (range 13-79) days after index biopsies. In those cases, allograft function was preserved and the final serum creatinine level was 2.14 ± 1.19 (0.80-4.55) mg/dL after 962 ± 393 (325-1563) days of follow-up. Two cases with persistent urinary decoy cells shedding lost their graft 195 and 362 days later. Amongst 29 repeat biopsies, there were 13 TAg-positive and 16 negative biopsies. In 12 of 13 TAg-positive biopsies (92%), urinary decoy cells were still positive, whereas at the same time in 15 TAg-negative biopsies, decoy cells had already disappeared (94%). CONCLUSIONS Cytology testing is advantageous because of its cost effectiveness. Clearance of decoy cells from urine was closely related to histological remission of BKVN, and may possibly be a therapeutic target in BKVN.

Effect of Cell Permeable Peptide of c-Jun NH2-Terminal Kinase Inhibitor on the Attenuation of Renal Ischemia-Reperfusion Injury in Pigs

The outcomes of organ transplantation have improved due to better immunosuppressive drugs, surgical techniques, and management of complications. However, ischemia-reperfusion injury remains a challenge affecting graft survival. In this study, we employed injection of a protein transduction domain (PTD) to inhibit the c-Jun NH2-terminal kinase (JNK) pathway thereby attenuating ischemia-reperfusion injury in a porcine model. The PTD-JNK inhibitor (JNKI) was administered into the renal artery, allowing it to be taken into various elements including vascular endothelial cells by endocytosis via the PTD. Serum creatinine and blood urea nitrogen concentrations were lower among PTD-JNKI than controls. In addition, renal tissue blood flow was maintained in the PTD-JNKI group, resulting in less tissue injury and fewer apoptotic cells. These results suggested that the PTD technique improved renal transplantation outcomes.

Renal interstitial fibrosis in 0-hour biopsy as a predictor of post-transplant anemia.

Background/Aims: Anemia is common in kidney transplant patients and may cause adverse cardiovascular events. Several studies have reported some predictors of post-transplant anemia. However, associations between the pathological findings in the 0-hour biopsy and anemia have not been well described. Methods: 258 consecutive kidney transplant patients were enrolled in this retrospective study. The patients were divided into two groups, according to the presence or absence of interstitial fibrosis and tubular atrophy (IF/TA) in the 0-hour biopsy: the IF/TA group with fibrotic area ≥5% (n = 131) and the non-IF/TA group with fibrotic area <5% (n = 127). We examined the association between IF/TA and post-transplant anemia. Results: Serial changes in hemoglobin levels in the IF/TA group were lower than in the non-IF/TA group (p = 0.007). Anemia at 12 months was found in 53% of the IF/TA group, and 35% of the non-IF/TA group (p = 0.004). Even after adjustment for several confounders including graft function, the presence of IF/TA was independently associated with post-transplant anemia at 12 months (odds ratio 1.88, 95% confidence interval 1.06-3.36, p = 0.031). This association was still significant in a subgroup with normal graft function. Conclusions: IF/TA in the 0-hour biopsy specimen is one of the predictors for post-transplant anemia and can be used to identify patients who need the treatment with erythropoiesis-stimulating agents.

Incidence of Hepatitis B Viral Reactivation after Kidney Transplantation with Low-Dose Rituximab Administration

Background In hematological malignancy patients intended to receive rituximab, hepatitis B virus (HBV) serology screening, viral reactivation monitoring, are recommended. However, the effect of single-dose rituximab (RIT) on HBV reactivation in kidney transplant patients with previous HBV infection is still unclear. Methods In this retrospective cohort study consisting of 1294 kidney transplant patients, we identified 76 patients showing preoperative hepatitis B surface antigen–negative, hepatitis B core antibody–positive, and HBV-DNA–negative results. A rituximab dose of 200 mg/body was administered to 48 patients, 46 of whom did not receive prophylaxis (RIT+ group). Twenty-eight patients received neither rituximab nor prophylaxis (RIT− group). We monitored HBV-DNA by polymerase chain reaction every 1 to 3 months, and HBV reactivation was defined as detectable HBV-DNA. Results HBV reactivation was found in 1 patient in the RIT+ group (2.2%) and 1 patient in the RIT− group (3.6%) at 6 weeks and 5.5 years posttransplant, respectively, but spontaneously cleared. Both patients showed positive hepatitis B surface antibody preoperatively. HBV reactivation was not found in 6 patients lacking anti-hepatitis B surface preoperatively. Conclusions Low-dose RIT administration in kidney transplant patients without prophylaxis is associated with low incidence of HBV reactivation. However, the comparisons among standard-dose RIT, low-dose RIT, and controls with high-quality study design is necessary.

Histological Analysis in Abo-compatible and Abo-incompatible Kidney Transplantation by Performance of 3- and 12-month Protocol Biopsies.

Background ABO-incompatible (ABO-I) kidney transplantation (KTx) is an established procedure to expand living donor sources. Although graft and patient survival rates are comparable between ABO-compatible (ABO-C) and ABO-I KTx, several studies have suggested that ABO-I KTx is associated with infection. Additionally, the histological findings and incidence of antibody-mediated rejection under desensitization with rituximab and plasmapheresis remain unclear. Methods We reviewed 327 patients who underwent living-donor KTx without preformed donor-specific antibodies (ABO-C, n = 226; ABO-I, n = 101). Patients who underwent ABO-I KTx received 200 mg/body of rituximab and plasmapheresis, and protocol biopsy (PB) was planned at 3 and 12 months. We compared the PB findings, cumulative incidence of acute rejection in both PBs and indication biopsies, infection, and patient and graft survivals. Results The 3- and 12-month PBs were performed in 85.0% and 79.2% of the patients, respectively. Subclinical acute rejection occurred in 6.9% and 9.9% of patients in the ABO-C and ABO-I groups at 3 months (P = 0.4) and in 12.4% and 10.1% at 12 months, respectively (P = 0.5). The cumulative incidence of acute rejection determined by both PBs and indication biopsies was 20.5% and 19.6%, respectively (P = 0.8). The degrees of microvascular inflammation and interstitial fibrosis/tubular atrophy were comparable. Polyomavirus BK nephropathy was found in 2.7% and 3.0% of patients in the ABO-C and ABO-I groups, respectively (P = 1.0). The incidence of other infections and the graft/patient survival rates were not different. Conclusions Analyses using 3- and 12-month PBs suggested comparable allograft pathology between ABO-C and ABO-I KTx under desensitization with low-dose rituximab and plasmapheresis.

Immobilization-induced severe hypercalcaemia successfully treated with reduced dose of zoledronate in a maintenance haemodialysis patient

improvement in creatinine, a kidney biopsy was performed, revealing oxalate nephropathy (Fig. 1). On further history, over the past week he had commenced a weight loss programme, consuming three beetroots and radishes with leaves daily. Additionally, he consumed tea, spinach and 500 g of walnuts weekly. There were no symptoms to suggest a primary gastrointestinal aetiology and faecal samples were normal. Given the acute presentation and temporal relationship to diet, it was felt that primary oxalosis was less likely, favouring a diagnosis of oxalate nephropathy secondary to excessive dietary intake. Subsequently renal function improved, with a normal 24 h urinary excretion of oxalate. Oxalate nephropathy is an important cause of renal injury. Secondary oxalate nephropathy is uncommon and causes include enteric and dietary aetiologies. Normal dietary oxalate intake is 80–120 mg/day, with a significant proportion excreted in the gastrointestinal tract. It is difficult to estimate the exact oxalate content of foods given significant geographical and seasonal variability, however beetroots, spinach and nuts are all high in oxalate. Another feature of this case was the history of vitamin C supplementation. A breakdown product of vitamin C is oxalate and other case studies have reported oxalate nephropathy secondary to excessive vitamin C. Cessation of a diet and supplements high in oxalate resulted in a marked improvement in serum creatinine. One-month post admission, his creatinine was 131 μmol/L. Whilst dietary related oxalate nephropathy is rare, this case highlights the importance of dietary history and kidney biopsy in an otherwise unexplained case of acute renal failure with a bland urinary sediment. The authors thank Professor D. Power for his assistance with this case.